Rapid neurogenesis through transcriptional activation in human stem cell (Agilent)
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ABSTRACT: Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two murine Neurogenin transcription factors in human induced pluripotent stem cells, and obtained neurons with bipolar morphology in four days at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the transition from stem cell to neuron. These profiles were then analyzed to identify the regulatory networks underlying the differentiation of the neurons. The arrays presented here assessed the differences between single neurogenin and dual neurogenin expression.
Project description:Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two murine Neurogenin transcription factors in human induced pluripotent stem cells, and obtained neurons with bipolar morphology in four days at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the transition from stem cell to neuron. These profiles were then analyzed to identify the regulatory networks underlying the differentiation of the neurons.
Project description:Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two murine Neurogenin transcription factors in human induced pluripotent stem cells, and obtained neurons with bipolar morphology in four days at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the transition from stem cell to neuron. The miRNA profiles were then analyzed to identify the miRNAs involved in the differentiation of the neurons.
Project description:Advances in cellular reprogramming and stem cell differentiation now enable ex vivo studies of human neuronal differentiation. However, it remains challenging to elucidate the underlying regulatory programs because differentiation protocols are laborious and often result in low neuron yields. Here, we overexpressed two murine Neurogenin transcription factors in human induced pluripotent stem cells, and obtained neurons with bipolar morphology in four days at greater than 90% purity. The high purity enabled mRNA and microRNA expression profiling during neurogenesis, thus revealing the genetic programs involved in the transition from stem cell to neuron. These profiles were then analyzed to identify the regulatory networks underlying the differentiation of the neurons. Paired end RNA sequencing of iPS cells (PGP1) at 0, 1, 3, and 4 days post- doxycycline induction of murine NGN1 and NGN2. This was done using an Illumina HiSeq, and reads were aligned to hg19
Project description:Human neurons engineered from induced pluripotent stem cells (iPSCs) through Neurogenin 2 (Ngn2) overexpression are widely used to study neuronal differentiation mechanisms and to model neurological diseases. However, the differentiation paths and heterogeneity of emerged neurons have not been fully explored. Here we used single-cell transcriptomics to dissect the cell states that emerge during Ngn2 overexpression across a time course from pluripotency to neuron functional maturation. We find a substantial molecular heterogeneity in the neuron types generated, with at least two populations that express genes associated with neurons of the peripheral nervous system. Neuron heterogeneity is observed across multiple iPSC clones and lines from different individuals. We find that neuron fate acquisition is sensitive to Ngn2 expression level and the duration of Ngn2 forced expression. Our data reveals that Ngn2 dosage can regulate neuron fate acquisition, and that Ngn2-iN heterogeneity can confound results that are sensitive to neuron type.
Project description:During neocortical development, neurons undergo polarization, oriented migration, and layer type-specific differentiation. The transcriptional programs underlying these processes are not completely understood. Here we show that the transcription factor Bcl11a regulates polarity and migration of upper layer neurons. Bcl11a-deficient late-born neurons fail to correctly switch from multipolar to bipolar morphology resulting in impaired radial migration. We show that the expression of Sema3c is increased in migrating Bcl11a-deficient neurons and that Bcl11a is a direct negative regulator of Sema3c transcription. In vivo gain-of-function and rescue experiments demonstrate that Sema3c is a major downstream effector of Bcl11a required for the cell polarity switch and for the migration of upper layer neurons. Our data uncover a novel Bcl11a/Sema3c-dependent regulatory pathway used by migrating cortical neurons. Neocortex tissue from three control (Bcl11a+/+) and three Bcl11a mutants (Bcl11aΔflox/Δflox) embryos was collected at E14.5. Total RNA was isolated from each sample separately using the RNeasy kit (Qiagen). The isolated ENA was inspected for integrity and purity using an Agilent Bioanalyzer and a NanoDrop spectrophotometer, respectively. Microarray analyses were performed using 200 ng total RNA as starting material and 5.5 µg ssDNA per hybridization in a GeneChip Fluidics Station 450 (Affymetrix). The total RNAs were amplified and labeled following the Whole Transcript (WT) Sense Target Labeling Assay (Affymetrix). Labeled ssDNA was hybridized to Mouse Gene 1.0 ST Affymetrix GeneChip arrays (Affymetrix). The chips were scanned with a GeneChip Scanner 3000 (Affymetrix) and subsequent images analyzed using Affymetrix Expression Console Software (Affymetrix). A transcriptome analysis was performed using BRB-ArrayTools developed by Dr. Richard Simon and BRB-ArrayTools Development Team (http://linus.nci.nih.gov/BRB-ArrayTools.html).
Project description:Hypothalamic gonadotropin-releasing hormone (GnRH) neurons lays the foundation for human development and reproduction, however, the critical cell populations and the entangled mechanisms underlying the development of human GnRH neurons remain poorly understood. Here, by utilizing our established human pluripotent stem cells-derived GnRH neuron model, we decoded the cellular heterogeneity and differentiation trajectories at the single-cell level. We found that a glutamatergic neuron population, which generated together with GnRH neurons, showed similar transcriptomic properties with olfactory sensory neuron and provided the migratory path for GnRH neurons. Through trajectory analysis, we identified a specific gene module activated along the GnRH neuron differentiation lineage, and we examined one of the transcription factors, DLX5, expression in human fetal GnRH neurons. Furthermore, we found that Wnt inhibition could increase DLX5 expression, and improve the GnRH neuron differentiation efficiency through promoting neurogenesis and switching the differentiation fates of neural progenitors into glutamatergic neurons/GnRH neurons. Our research comprehensively reveals the dynamic cell population transition and gene regulatory network during GnRH neuron differentiation.
Project description:A complex train of events unfolds during brain development, guided by activation/repression of gene expression programs. It remains unclear how this process is disrupted in disease. Here we integrate human genetics with transcriptomic data from differentiation of human embryonic stem cells into cortical excitatory neurons. This reveals a cascade of transcriptional programs activated during early corticoneurogenesis in vitro and in vivo. Genetic variation in these programs is robustly associated with neuropsychiatric disorders and cognitive function, with variants concentrated in loss-of-function intolerant genes. Neurogenic programs also capture schizophrenia GWAS enrichment previously identified in mature excitatory neurons, suggesting that pathways activated during pre-natal development underlie disease-relevant deficits in mature neuronal function. Down-regulation of these programs in DLG2-/- lines delays expression of cell-type identity and impairs neuronal migration, morphology and action potential generation, validating predicted deficits. These data implicate specific cellular pathways underlying neurodevelopment in the aetiology of multiple neuropsychiatric disorders and cognition.
Project description:Transcriptional targets of neurogenin (Ngnr1) were identified by over-expression of an inducible form of neurogenin in Xenopus ectodermal explants. The effects of co-expressing the nucleoprotein geminin on Ngnr1-dependent target gene transactivation were defined. Regulating the transition from lineage-restricted progenitors to terminally differentiated cells is a central aspect of nervous system development. Here, we investigated the role of the nucleoprotein geminin in regulating neurogenesis at a mechanistic level during both Xenopus primary neurogenesis and mammalian neuronal differentiation in vitro. The latter work utilized both neural cells derived from embryonic stem and embryonal carcinoma cells in vitro and neural stem cells from mouse forebrain. In all of these contexts, geminin antagonized the ability of neural bHLH transcription factors to activate transcriptional programs promoting neurogenesis. Furthermore, geminin promoted a bivalent chromatin state, characterized by the presence of both activating and repressive histone modifications, at genes encoding transcription factors that promote neurogenesis. This epigenetic state restrains the expression of genes that regulate commitment of undifferentiated stem and neuronal precursor cells to neuronal lineages. Geminin is highly expressed in undifferentiated neuronal precursor cells but is downregulated prior to differentiation. Therefore, these data support a model whereby geminin promotes the neuronal precursor cell state by modulating both the epigenetic status and expression of genes encoding neurogenesis-promoting factors. Additional developmental signals acting in these cells can then control their transition toward terminal neuronal or glial differentiation during mammalian neurogenesis. A dexamethasone-inducible (GR ligand binding domain fused) form of Xenopus neurogenin-related 1, NgnrGR, was over-expressed in Xenopus embryonic ectodermal explants, in the presence or absence of over-expressed geminin. Induction of Ngnr1 activity was used to define direct targets as previously described (EMBO J. 26(24): 5093-5108). The ability of geminin to suppress Ngnr1-dependent transactivation of its target gene programs was determined.
Project description:During neocortical development, neurons undergo polarization, oriented migration, and layer type-specific differentiation. The transcriptional programs underlying these processes are not completely understood. Here we show that the transcription factor Bcl11a regulates polarity and migration of upper layer neurons. Bcl11a-deficient late-born neurons fail to correctly switch from multipolar to bipolar morphology resulting in impaired radial migration. We show that the expression of Sema3c is increased in migrating Bcl11a-deficient neurons and that Bcl11a is a direct negative regulator of Sema3c transcription. In vivo gain-of-function and rescue experiments demonstrate that Sema3c is a major downstream effector of Bcl11a required for the cell polarity switch and for the migration of upper layer neurons. Our data uncover a novel Bcl11a/Sema3c-dependent regulatory pathway used by migrating cortical neurons.